The subject matter disclosed herein relates to a dual disk check valve and, more particularly, to a dual disk check valve with a slotted stop bar.
Dual disk check valves are employed in various types of ductwork and piping and utilize pivoting disks that are commonly referred to as flappers. The flappers swing open and close depending on the corresponding direction of fluid flow through the ductwork. When the valve opens during normal conditions, it is imperative that the disks do not swing near or over the center position due to the typical configuration of dual disk check valves. If such a condition occurs, net forces on the upstream side of the disks could hold the check valve open during reverse flow conditions. This would prevent the check valve from performing its primary function of preventing reverse flows by closing.
In a common method of preventing the disks from opening too much, a “stop pin” is employed. The disks hit the pin at a predetermined angle, which is usually no more than 80 degrees, and stop swinging open. However, because the disks are typically swinging open at maximum velocity when they hit the pin, the pin needs to be relatively stiff. Thus, an impact load occurs when the disk(s) hits the pin. Over many cycles, these high loads can fatigue the disks or the pin and cause either to fracture. Fracture would be considered a catastrophic failure since loose metal parts could be released into a fluid stream.